Since the successful introduction of all-trans-retinoic acid (ATRA) and its combination with anthracycline-containing chemotherapy, the prognosis for acute promyelocytic leukemia (APL) has markedly improved. With ATRA and anthracycline-based-chemotherapy, the complete remission rate is greater than 90%, and the long-term survival rate is 70-89%. Moreover, arsenic trioxide (ATO), which was introduced for APL treatment in 1994, resulted in excellent remission rates...